Mitsubishi Electric MELSEC iQ-R Series User Manual page 263

■Registered portion of 2-byte data for code of registration data, FFH+00H to FFH
C24 receives and checks if the received data is variable data corresponding to the combination of the registered codes FFH
and 00H to FFH.
For example, if a sum check code is registered, C24 calculates the sum check code from the receive data and checks if it is
the same as the received sum check code. If the two codes are not the same, C24 performs error processing.
If C24 station number is registered, C24 checks if the received station number is the same as the station number set in C24. If
the two station numbers are not the same, C24 processes the data as if normal data was received instead of a user frame.
Ex.
When data code 03H, FFH, F0H, 0DH, 0AH is registered as user frame number, 3E9H
When user frame No. 3E9H is set for data reception, C24 calculates, receives, and checks the sum check code as the receive
data of that user frame portion.
■In a reception message
C24 removes the user frame data portion from the reception message.
(The CPU module cannot read this data.)
■Remarks
With the multidrop connection, the module on a given station stores only arbitrary data portion of a message transmitted by
the target device in the receive data storage area by registering each receive user frame specific to respective modules to be
connected.
(First frame)
Data when a receive frame is
received at each C24
(Last frame)
Target device
Data used by the target device to indicate the transmission destination
S
Arbitrary
;
T 5 A
data
X
CPU C24 CPU
(0)
S
T 0 A ;
X
C L
;
R F
13 CONTENTS AND REGISTRATION OF USER FRAMES FOR DATA COMMUNICATION
13.2 Transmission/Reception Processing Using User Frame Registration Data
C L
;
R F
Received by the station No.5 C24.
C24 CPU C24
(1) (5)
S S
T 1 A ; T 5 A
X X
C L C L
; ;
R F R F
( ): Station No.
;
13
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